Dutch scientist Dr. Bart Knols first discovered mosquitoes were attracted to foot odor by standing in a dark room naked and examining where he was bitten, said Dr. Fredros Okumu, the head of the research project at Tanzanias Ifakara Health Institute. But over the following 15 years, researchers struggled to put the knowledge to use.

Then Okumu discovered that the stinky smell  which he replicates using a careful blend of eight chemicals  attracts mosquitoes to a trap where they can be poisoned. The odor of human feet attracted four times as many mosquitoes as a human volunteer and the poison can kill up to 95 percent of mosquitoes, he said.

Malaria study raises doubt about effectiveness of program...Study raises doubts about effectiveness of malaria programFri, Aug 19, 2011 : Insecticide-treated bednets, whose use is being widely promoted in Africa to combat malaria, may paradoxically be linked to local resurgence of the disease, according to concerns raised by a study yesterday.

Based on observations in a village in Senegal, the study points to evidence that mosquitoes develop resistance to the insect-killing chemical that coats the nets. In addition, people may lose their immunity to the malaria parasite when the mosquito population is in decline and then become exposed when the insect pest recovers, it suggests. Doctors led by Jean-Francois Trape of the Institute for Development Research in Dakar sought to assess the impact of bednets that were introduced in the central village of Dielmo in August 2008. A year and a half before the operation, the team checked more than 500 villagers for sickness from malaria and studied local populations of mosquitoes. They pursued this work over the next four years, in an exceptionally detailed probe.

From August 2008 to August last year, incidence of malaria fell dramatically, to less than 8 percent of the pre-scaleup level, the investigators found, but between September and December last year, the numbers rose sharply again, to where incidence was 84 percent of previous levels. Among adults and children aged 10 or more, the rate was even higher than before. The researchers found that the proportion of Anopheles gambiae mosquitoes with a genetic variant conferring resistance to pyrethroid  the insecticide used in the netting  had risen from 8 percent in 2007 to 48 percent late last year. These findings are of great concern, Trapes team reported in the British journal The Lancet Infectious Diseases.

They support the idea that insecticide resistance might not permit a substantial decrease in malaria morbidity in many parts of Africa where A. gambiae is a vector and acquired clinical immunity is a key epidemiological factor. The suspicion  but not supported by clinical evidence in the study  is that older villagers gradually lost immunity to the malaria parasite as the threat receded and therefore became exposed when the mosquito population rebounded. Malaria claimed 781,000 lives in 2009, according to the WHO, which is spearheading the campaign to distribute insecticide-treated nets and spray reproduction sites. About 90 percent of malaria deaths each year occur in Africa and 92 percent of those are children aged under five.

In a commentary, Joseph Keating and Thomas Eisele, specialists at Tulane University in New Orleans, cautioned against leaping to conclusions. They praised the study for its thoroughness, but said its duration was too short and focused only on one village in rural Senegal. By itself, this is not enough to confirm that the bednet program is flawed or that the same problems apply across Africa, the pair said.

Granny says God made mosquitoes to bug us...Spermless mosquitoes could help halt malaria spreadMon Aug 8, 2011 - Releasing genetically modified, spermless male mosquitoes into the wild could in future help to prevent malaria transmission and reduce the chances of large outbreaks of the killer disease, British scientists said on Monday.

Researchers from Imperial College London sterilized male mosquitoes by genetically modifying them to neutralize a gene required for sperm production. In a study to see how these mosquitoes would fare when trying to get a mate, they found that female mosquitoes cannot tell if the males they mate with are fertile, or spermless and therefore unable to fertilize the females' eggs.

The researchers said findings suggest that in future it might be possible to control the size of the malaria-carrying mosquito population by introducing a genetic change that makes males sterile. Female mosquitoes would then unknowingly mate with the modified males and fail to produce any offspring. Malaria is a mosquito-borne disease that affects up to 300 million people and kills nearly 800,000 every year. Its threat is greatest in Africa, where the World Health Organization says a child dies of malaria about every 45 seconds.

Public health experts are working toward the eventual global eradication of malaria, but progress is slow and there is a constant need for better and cheaper ways to get there. "In the fight against malaria, many hope that the ability to genetically control the mosquito vector will one day be a key part of our armory," said Flaminia Catteruccia from Imperial's life sciences department, who led the study.

But she added that for these currently theoretical control ideas to work in practice, scientists have to establish whether the insects would continue to mate as normal, unaware that their sexual mechanisms had been tampered with.

Malaria vaccine makes good showing in clinical trials...Malaria Vaccine Shows Acceptable Safety, Efficacy ResultsOctober 18, 2011 - An international health alliance working to develop a vaccine against malaria says one of its most advanced vaccines, called RTS,S, shows promising results. After two years of human clinical trials in Africa, the PATH Malaria Vaccine Initiative and its collaborators report the vaccine provides protection against malaria for children aged five to 17 months.

Scientists working on the worlds first-ever malaria vaccine are calling the RTS,S trials a significant milestone. For 40 years people have been trying to develop malaria vaccine and here we are, said Dr. Christian Loucq, the director of Malaria Vaccine Initiative, which is an international non-profit group involved in assessing the safety and effectiveness of the new vaccine. Thousands of children in seven countries in Africa received the vaccine. Investigators found that in vaccinated children, the risk of severe and clinical malaria was reduced by half. Phase Three is where you look into efficacy and safety for which we had consistent results and we are very happy and encouraged to move on, said Dr. Daniel Ansong, a pediatrician and researcher at one of the clinical-trial sites in Ghana.

Dr. Ansong believes the vaccine will be a valuable new weapon in the global war on malaria. Critics note that in the field trials, the new vaccine was only 47 percent effective against severe malaria, a level of protection they say should be higher. But pediatricians say that with malaria killing 800,000 children every year, even this level of efficacy could save thousands of lives. Dr. Joe Cohen is co-inventor of the RTS,S vaccine and a researcher at the drug companty GlaxoSmith-line. It has invested $300 million in malaria vaccine development. Cohen says developing a vaccine against malaria has been a major scientific challenge. The problem, I think, is the parasite itself. Malaria parasite - parasites in general - very complex organisms, with complex DNA makeup with many thousands of genes, in contrast to bacteria or viruse, he said.

GlaxoSmith-Kline says it expects to invest an additional $50 to 100 million in the vaccine program. Researchers say they will start testing the vaccine on larger populations after the successful completion of ongoing Phase Three trials. The developers plan to submit the final results of the vaccine trials to the World Health Organization by 2014. Their hope is that the WHO will recommend that the malaria vaccine become a routine part of all future childhood immunization programs.

Approaching malaria vaccine from a different direction...New approach to malaria vaccine revealed by Oxford researchers20 December 2011 - Malaria is caused by parasites injected into the blood by infected mosquitoes

A potential new malaria vaccine has shown promise in animal studies, according to research. An Oxford University team is to start safety trials in human volunteers after lab tests showed the vaccine works against all strains of the parasite. UK scientists recently found the route malaria uses to enter blood cells. They hope to target this pathway in a new approach to developing a vaccine against malaria, which kills hundreds of thousands of people a year. Several potential malaria vaccines are already being tested in clinical trials; although no vaccine has yet been licensed for use.

Early clinical trials in Africa suggest a vaccine known as RTS,S appears to protect about half of people vaccinated from malaria. While these results are encouraging, some scientists believe a more effective vaccine is needed to fight the disease. One possibility is to exploit a recently-discovered potential weakness in the parasite's life cycle. A team at the Sanger Institute found in November that a single receptor on the surface of red blood cells and a substance known as "PfRh5" on the parasite are crucial to the success of malaria in invading blood cells. Early lab tests suggest a vaccine against the protein may prove effective, at least in animals.

Dr Sandy Douglas is a Wellcome Trust Clinical Research Training Fellow from the University of Oxford and first author on the study, published in the journal, Nature Communications. He told the BBC: "We have found a way of making antibodies that kill all different strains of malaria parasites. This is still early phase research in animals. The next step is to do clinical trials in people." If safety tests of the vaccine prove successful, clinical trials in patients could begin within the next two to three years, says the Oxford team. Dr Gavin Wright, from the Wellcome Trust Sanger Institute, said recent findings on how the malaria parasite invades red blood cells were unexpected. Dr Wright, a co-author on both studies, added: "It revealed what we think is the parasite's Achilles heel in the way it invades our cells and provided a target for potential new vaccines."

A new malaria prevention strategy might literally be blowing in the wind. A team of scientists studying the patterns of malaria infection in rural Kenyan villages noticed that, despite a gradual reduction of malaria cases in the region, hotspots persisted. The blood-sucking mosquitos that transmit the malaria parasite to humans breed in water. So the researchers decided to examine the location of those breeding ponds in relation to the most infected villages. Their findings are published this week in Nature Communications.

Co-author David Smith, an epidemiologist with the Johns Hopkins Bloomberg School of Public Health in Baltimore, Maryland, says a curious pattern emerged. In this study what we did is we looked at the locations of aquatic habitats and the locations of humans and we were trying to find out if there was some kind of clustering, which there should be and of course there was. But as we looked even closer what we found was that there was an association between the direction of the wind and the location of where people were at risk.

Smith says while mosquitos arent particularly good flyers, their flight pattern is directed by the scent of a potential human host. We had a hypothesis that since scents travel down wind, that the mosquitos were actually tacking across the wind until they found one of those odor plumes and then tacking upwind until they found it. We should expect to find that places with higher risk were upwind of larval habitat. Smith and his research team studied 642 children living in Kenyan villages after the rainy season, when malaria peaks.

Janet Midega is a medical entomologist with the Kenya Medical Research Institute and co-author of the study. She says scientists compared the malaria case data with the proximity of stagnant water pools. What we did find was a lot of the pools of water did have immature mosquito stages, and so we sampled these pools of water. We sampled these mosquitos and identified them as the mosquito species that is responsible for malaria transmission in the area. The study found that the shorter the distance from those larval incubators, the higher the prevalence of malaria.

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